Tachographs for motor vehicles, in particular for heavy goods vehicles, detect and evaluate data relating to a journey and to a driver of the motor vehicle and are known in practice. The smart card is used, inter alia, to store the data relating to the driver, which data is generated in the tachograph, and has a chip with contact areas with which spring contacts, which are arranged in the shaft, make contact. A problem can arise when transmitting data to the smart card if the spring contacts or the contact areas are dirty or corroded. In this case, the data can no longer be transmitted from the tachograph to the smart card and, in the worst-case scenario, a relatively large amount of data is lost. Equally, when the card has already been inserted in the shaft for a relatively long time, the connection between the spring contacts and the contact areas can be impaired due to temperature and moisture influences.